soribner



(No Model.) 2 Sheets-Sheet 1. C. E. SCRIBNBR.

SPRING JACK SWITCH. y

No. 552,729. Patented Jen. 7, 1896.

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2 Sheets-Sheet 2.

(Nomodel.)

G. E. SGRIBNER.

SPRING JACK SWITCH. l No. 552,729.- Patented Jan. 7,1896.'

WITNEEEEE I {NVEN z Y NETED. STATES PATENT OFFICE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE VESTERN i ELECTRIC COMPANY, OF SAME PLACE.

SPRING-JACK SWlTCH.

SPECIFICATION forming part of Letters lPatent No. 552,729, dated January '7, 1896. Appui-.ation filed May 9,1893. serial No. 473,585. (No moda.)

To @ZZ whom t may concern:

Be it known that I, CHARLES E. SCRIBNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Sprin g-Jack Switches, (Case No. 333,) of which the followingis a fulhclear,`

tacts shall be accessible for testing to determine the insulation and continuity of the circuit-wires.

In telephone-switchboards of the multiple type it is usual to provide a spring-jack or terminal socket upon each section of the multiple switchboard for each line.

nect the remainder of the circuit through the switchboard. The long-distance connections or other connections requiring the highest insulation and greatest freedom from disturbance are made with this first spring-jack of the series by means of the usual loop-plug, in order to free the line from the disturbances arising from cross-talk or induced currents taking place in the cables of the switchboard, and the shunting effect ofthe annunciator which is permanently connected with the switchboard-circuit. The necessity also frequently arises of testing to locate defects upon the line, which defects may be either in the switchboard or upon the line-circuit, and such tests have been provided for by a second switch in the line or switchboard circuit adapted to open the line-circuit in order that the circuit through the switchboard and that through the line might be separately tested. The spring -jack switches have usually been arranged in groups of twenty, the different members of the group being mounted upon a common base-plate, the aggregation being denominated a strip of spring-jacks.

The first spring-jack of the series is arranged in the form of a switch which is adapted to discon- 4the stem online 12 12 of Fig. 10.

Since the capacity of a telephone-'exchange is to a large extent limited by the number of spring-jacks which can be grouped within reach of an operator, it becomes essential that these spring-jacks shall be as smallas possible consistent with the durability and insulation of their parts.

In my inventionI have aimed to produce a simple and durable strip of spring-jack 6o switches whose contact-points are' not only adapted to make connection with the corresponding portions ofthe ordinary connectingplugs, but which are also accessible for testing by means of a specially-constructed testing-plug which I have provided, by which separate circuits may be closed through the switchboard-circuit and through the line-circuit simultaneously. My improved springjack is also provided with the usual local 7o contact-pieces which are connected with the annunciator for the purpose of restoring it and for testing purposes.

My invention is illustrated in the accompanying drawings and will be described in full in connection therewith.

In the drawings, Figure l is a plan of a strip of twenty spring-jacks constructed in accordance with my invention. Fig. 2 is a front elevation of the strip. Fig. 3 is a view 8o of the same from beneath. Fig. 4 is a rear elevation of the strip. Fig. 5 is a transverse section through the strip, taken upon the center line of a spring-jack. Fig. 6 is a longitudinal section of three spring-jacks on the 8 5 line 6 6 of Fig. 1. Fig. 7 is a perspective view of a section of the strip, the parts being removed from their-places `in the strip, and the parts of one spring-jack being displayed above the strip. Fig. S is a side elevation 9o of the special testing-plug which I have provided. Fig. 9 is a longitudinal vertical section of the plug. Fig. 10 is a view showing the plug in partial longitudinal horizontal soction. Fig. 1l is an end elevation of the 95 plug. Fig. 12 is a transverse section through Fig. 13 is a transverse section on line 13 13 of Fig. 10. Fig. 1i is a transverse section on line 14 14. of Fig. l0. Fig. 15 is a diagram showingthe 10o testing-pluginserted into a spring-jack which is connected with a line-circuit and a switchsunk at the front of the strip.

board-circuit, a switch and galvanometerbeing shown in circuit with the test-plug. Fig. 10 is adiagram showing the ordinary threepart plug inserted in the same spring-jack in place of the testing-plug.

The parts of the spring-jacks are mounted upon the common plate a, which is preferably of hard rubber or other insulating material, in suitable recesses provided for them.

As may be best seen in the diagrams Figs. l5 and 16, each spring-j ack switch comprises, essentially, a pair of line-springs b U, which constitute the line connections of the springj ack, their co-operatin g switch-contact anvils c d, and two short thimbles d and c. The line-springs b b are adapted to be separated from their contact-anvils c c' by an inserted plug, the line-sprin gs making connection with corresponding contact-pieces upon the plug, while the two thimbles CZ and e are arranged to be crossed together through the metallic sleeve or shell of the plug. The line-springs b b of a spring-jack and the springs c c,which constitute theirrespective contact-anvils, are arranged together in a group or bundle, the different springs being separated by tongues ff f2 of hard rubber or other flexible insulating material. Two perforations g and g are made in each of the springs and rubber tongues of one spring-jack, and insulatingpins 7L and 7d are inserted into the perforations extending through the group of springs and tongues and holding them in place with respect to each other. The entire group is then inserted into a groove a in the strip a. This groove is of sufficient depth to bring the upper edges of the springs a little below the upper surface of the strip a. The groove a is sufficiently wide throughout most of its length to permit free play of the springs b Z9 when they are forced downward by an inserted plug; but it is contracted at the rearportion so as to fit the group of springs tightly to hold them in place. In order to insure their rigid retention'in place, two screws t' and t" are screwed down into countersunk holes in the strip a, so that the heads of the screws come below the surface of the strip in such position that the heads overlap upon the springs l1 and prevent their slipping out of the groove a', notches if t3 being cut in the springs to permit the screw-heads to be brought down to the proper level. Thus when the bundle of springs b b', contact -pieces c and c', and tongues f, j", and f2 have been pinned together bythe pins 7L and forced into the groove a', and the screws t' are screwed down into place, the parts are heldsecurely from motion in any direction, while at the same time the means employed for thus securing them are exceedingly compact and permit of close arrangement of thespringjacks upon the plate a. In front of each pair of line-springs a cylindrical opening a3 is made in the plate a extending from the front of the groove ct/ to the front of thel strip, the opening' being counter- In this tubular opening the two thimbles d and e are mounted, fitting closely the opening. The thimble d is secured in place in the opening by means of a pin d driven into the thimble through the plate a. All the different thimbles d of the strip of spring-jacks are connected together by means of a ribbon 7e' of metal laid into a groove in the surface of the plate a, so as to come a little below the surface, through which ribbon the pins d pass and in which their upper extremities are soldered. The thimble e is provided with a shoulder which fits the countersunk portion of the tubular opening a3. This thimble is provided with a rearward extension c, which is led through an oblique duct in the plate a into a transverse saw-cut a4 on the under side of the strip to the rear of the strip, in order that connection may be made with the thimble e from the rear of the spring-jacks.

The springs l) and b/ have a downward curvature to bring their tips or curved extremities opposite the opening of the thimbles d and e, so as to make proper contact with the plug inserted through the openings. The floor o2 of the groove a is depressed at this point to allow free play to the extremities of the springs.

As shown in diagrams Figs. l5 and 1G, the springs b and b are connected with the limbs Z Z/ of the telephone line-circuit extending to A the telephone sub-station m. The contactsprings c and c are connected with the limbs n n/ of the circuit through the remainder of the telephone-exchange, including the annunciator o of the telephone line. The thimbles d and e may constitute the normally-disconnected terminals of the local circuit including the restoring-coil of the individual annunciator, or provided for testing purposes, 4in the well-known manner. To this end the thimbles cl, connected with the common ribbon 7c., may be grounded by means of the ribbon. Then lthe ordinary triple connectingplug, as p, is inserted into the spring-jack, Fig. 16, the line-springs b and 1)/ are separated from their contact-anvils c c' and make connection with the tip p and the short sleeve p2, respectively, while the thimble (Zand the thimble e are crossed together through the inetallic sleeve or shell p3 of the plug.

In testing to locate defects in a telephonecircuit my special plug q, Figs. 8 to l5, is employed. This plug is constructed with four contact-pieces7 two, 'q' and q2, being arranged to make contact with the anvil-springs c d, while the other two contacts, Q3 g4, make connection with the line-springs b and b, the latter springs being at the same time lifted out of connection with their anvils c c'. The different contacts q Q2 and g3 g4 may be connected with the points of a switch in circuit with suitable testing appara-tus, so that by the movement of the switch the line-circuit Z Z to station m or the switchboard-circuit u n maybe tested. In the construction of this plug q I prefer to arrange the contact-pieces IOC IIO

IZO

q' and q2 together so as to constitute a thin stem having a hemispherical head, the stem and head being divided longitudinally by a thin strip of insulating material. The stem Vis inserted through a tube Q3 of metal, being serves to preserve it from contact with the thimbles CZ and e when the plug is inserted into the spring-jack. Binding-posts fr 7"12 are provided within the body Q7 of the plug to which the different contact-pieces q', q2, and Q3 are connected by means of wires, and with which the external testing-circuit may be connected by suitable leading-wires.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. rlhe combination with a telephone line of a spring jack having four contact pieces arranged in two pairs, whose members are separable, one pair being included in each line conductor, and a plug adapted to make connection with the four contact pieces; substantially as described.

2. The combination with a plate of insulating material having transverse grooves in one face and a plug-opening from the edge of the strip into the transverse groove, of line springs placed on edge and forced into the groove, the

^ springs being separated by an interposed tongue of insulating material, substantially as described.

3. The combination with the plate a having the groove a', of the line springs t and b separated by an interposed tongue of insulating material, forced on edge into the groove a', the groove being widened near the extremities of the springs to permit their play, as described.

fi. The combination with the plate a having the grooves a' formed in it, of the line springs b b and their contact springs c c separated by interposed tongues of insulating material, forced on edge into the groove, substantially as described.

5. The combination with the plate a having the groove a formed in it, of the line springs b t placed upon edge in the groove, and the screws 1111 screwed into the plate a with their heads overlapping the springs, whereby the springs are held in place, substantially as described.

6. The combination with the plate a having the perforations a3 formed in it, of the thimbles d in the perforations, the ribbon 7c upon the face of the strip, the ribbon being connected with the thimbles d by pins passing through the intervening portions of the plate a, substantially as described.

7. The combination with the plate a having the groove a and the corresponding opening as formed in it, of the springs b b lying in vertical planes, the ends thereof being transversely displaced to bring the ends down to the centerline of the opening, substantially as described.

8. The combination with the springs l) 1)/ and their corresponding contact springs c c', of the interposed rubber tongues ff f2 separating the different springs, and an insulating pin 71 extending transversely through the group of springs and contacts, substantially as described.

9. The combination with the plate a, of line springs b h and their contact springs c c' secured on edge in a transverse groove in the plate, and the thimbles d e in a transverse perforation in alignment with the springs, substantially as described.

10. The combination with a springjaclr having two line springs b b and two contact anvils c c' therefor, of a plug q inserted in the spring jack having contact pieces touching the two contact anvils c c', and contact sleeves making connection with the springs b and b', respectively, and lifting them from their respective contact anvils, substantially as described.

1l. The combination in a testing plug, of a stem terminating in a hemispherical head, thestem and head being longitudinally divided into contact pieces q q2, and the insulated sleeve qa concentric with the stem, substantially as described.

In witness whereof I hereunto subscribe my name this 19th day of April, A. D. 1893.

CHARLES E. SGRIBNER.

Witnesses:

ELLA EDLER, GEORGE L. CRAee. l

IOO 

